The present invention relates to a process and device for the measurement of a physical quantity of an extruded element preferably running through a cooling bath.
In the production of extruded synthetic plastics products or in the coating of conductors in the production of a cable, it is desired to determine the dimensions of the extruded element as soon as possible after they issue from the extruder, in order to correct possible errors as quickly as possible. The dimensions should be determined within the cooling bath directly connected with the extrusion nozzle rather than after the exit from the cooling bath. There are, however, various difficulties in effecting the measurement in the cooling bath. A measuring device projecting into the cooling bath from above not only hinders the introduction of the element into the cooling bath but also requires a certain minimum width of the cooling trough. It is difficult to effect a measurement without immersing components of the apparatus in the cooling trough, since the upper surface of the cooling liquid is turbulent and thus an exact optical measurement is impossible.